ckshman



A. SJCUSHMAN. METHOD OF PRODUCING COLOR EFFECTS.

APPLICATION FILED )UNE I0, 1921.

Patentd July 18, 1922.

2 SHEETS-SHEET A. s. CUSHMAN. METHOD OF PRODUCING COLOR EFFECTS.

APPLICATION FILED JUNE I0, I92!- Patented July is, 1922.

2 SHEETSSHEET 2.

III

I II

opn zpuE by an electric motor 5. a plurality of differently coloredpanes 3 UNITED I STATES PATENT OFFICE.

ALLERTON S. CUSHMAN, OF WASHINGTON, DISTRICT OF COLUMBIA.

METHOD OF PRODUCING COLOR EFFECTS.

Application filed June 10,

Ta all whom it may concern:

Be it known that I, ALLnn'roN S. CUSH- MAN, a citizen of the UnitedStates, residing at lVashington, in the District of Columbia, haveinvented certain new and useful Improvements in Methods of ProducingColor Effects, of which the following is a specification.

My invention relates to the art of produc ing color effects such as findmore general application, for instance, upon the stage.

It is known that owing to the phenomenon of persistence of vision thehumaneye is capable of retaining a visual impression for an appreciabletime which will vary accord ing to the intensity of the impression, thewave length of the light and the time involved in producing theimpression. By taking advantage of this phenomenon and so arranging andtiming the succession of separate beams of differently colored light andthe periods of occultation, I have discovered that I can produce new anduseful effects when such beams of light are directed upon movingobjects.

It is the general object of the invention to provide a method of and ameans for pro ducing fascinating color effects.

For a full understanding of the invention reference is had to theaccompanying drawings in which- Fig. 1 represents the generalarrangement of a device for carrying out the object of the invention andan object acted upon;

Fig. 2 is a front view of a device embodying the invention on anenlarged scale; and

Fig. 3 is a sideview thereof.

In the drawings 1 represents a usual form of projecting device foremitting a beam of light. In. front of the projecting device isrevolubly mounted a disk or wheel 2 driven This disk carries eparated byopaque portions 4.. The arrangement is such that the colored panes andopaque portions pass successively past the aperture of the projectingdevice.

The object is for the purpose of illustration represented as a bundle ofwhite streamers. 6 which under the influence of an agitating force ofany kind, as for instance a fan 7, is fluttering in the path of thelight beam.

When the disk 2 is revolved at a rate which will be more particularlyreferred to, the individual streamers appear as com- Specification ofLetters Patent.

Patented July 18, 19%2.

of operation, the number of objects to which the invention is applicableis without limit.

If, to cite another instance, a transparent receptacle containing wateris shaken, the moving drops appear to flow with all manner of varyingcolor.

An apparatus arranged under the general plan explained can be used forvarious purposes.

The principle on which the invention is based is probably as follows:

Assume that the rate of rotation of the disk is such that the successiveperiods of light emission through each pane are too short to satisfy thelaw of persistency of vision, a stationary or very slow moving objectwill appear in the color of the mixed light composed of the differentlight beams. Before the light due to one light beam has time to create afixed impression on the retina and cause a definite color sensationcorresponding to the wave length of the rays of that beam, the rayscoming from the next beam and reflected from the object are superimposedupon the first etc. The light effeet is that due to a more or lesseffective blending of all the light rays.

A white object thus will appear as white so long as this condition ismaintained, if the synthetic effect of the different beams issubstantially white light or it will appear in any other uniform coloraccording to the particular synthetic effect of the various beam will begradually allowed to pass until.

the ed e has reached'the lower limit of the b effective aperture of thePlOJGCtll'lg device.

When the lower edge of the next opaque portion gradually shuts off thelight from the top downwardly, the last rays of the beam are directeddownwardly.

Thus the beam is in effect traveling through a substantially verticalangle and therefore strikes the object first at the top and last at thebottom.

According to the relative positions of the projecting device and thedisk 2, the apparent motion of the beam can of course be changed asdesired.v Assume now that the object or a part of the object has. motioninthe direction of the traveling beam. and that its rate of motioncorresponds to that of the beam, The object ora part thereof, as thecase may be, is thus under the illuminating'effect of the light of aparticular light beam during the whole period of duration of the beam.If this period is long enough to satisfy the law of persistency ofvision, the color or a part thereof will appear in the color of thebeam.

as the case may be, will appear in. the colors of the plurality of:beams, such colors being juxtaposed. much like the colors of therainbow. This effect will take place only, however, if the time intervalduring which each color beam is allowed to act upon the object of theparts thereof satisfies the law of persista'ncy of vision.

The limiting conditions ofthe invention thus are; I Y Y 1. Thedifferently colored light beams must follow each other at such rate thatthe successive impulses are not sufliciently long to cause separatecolor sensations when the object is at rest.

2. The rate of projection must be such that during substantial motion ofthe object or parts thereof'light rays from the different beams persistlong enough to cause color sensations corresponding to the respectivebeams. I

3. Conversely the rate of projection must not be so high that during themotion of the object no. distinct and separate color sensation can beproduced.

. It is understood that the angular velocity of the disk 2 or theangular ratio of the opaque portions and transparent portions, or

'to a rotary disk.

both may be varied to suit particular conditions as to the rate ofmotion of the olnect or its parts.

I have found that a speed of 200-1000 rev- 'olutions per minute of thedisk gives satisfactory results with the usual movingobjects. j

The relativity of motion between the moving beams and the moving objectmay be varied within considerable range satisfying the law ofpersistei'nzy of vision and as a function of such variations the coloreffects produced upon the object or its parts vary correspondinglywithin wide limits. 7

The more separately movlng parts the object has and the more irregularand fantastic the movements of such parts are, the

more grotesque and bizarre is the color effect and the greater is therange of variations.

In fact the number and character of the different color effects islimited only by the creative faculty of the imagination.

In the foregoing reference has been made that a linear reciprocatingmovement'or any complex irregular movement will be equally or even moreeffective. There is, therefore, no limit in regard to the character ofmotion of the light beams.

There is likewise no limit in regard to the color values of the panesemployed nor to the form of the individual panes nor to the number ofthe panes on a disk nor to the relation of angular extent of the panesand opaqueportions or any of them, so long as the device is susceptibleof manipulation to bring about color effects such as referred to. inreality the invention can be carried out in various other Ways.alternate opaque and transparent I colored portions has been referred tomerely as a simple arrangement. i

It is obvious, however,

A disk composed of The periodical occultations essential for producingthe light effects described may be carried out by means of the variousforms of shutters well known in connection with the motion picture art;In the light of the-generalknowledge in this respect it is unnecessaryto illustrate shutter mechanisms for controlling the emission ofdiffer-,

ently colored light beams. WithinIthe scope of this invention colorscreens containing aplurality of differently colored sections may bemoved in front of the projecting device and the syncopations may beeffected by a shutter mechanism of any known type.

Within the scope of the invention a plurality of sources of differentlycolored light may be separately controlled by means of shutters so thatbeams of differently colored light may be intermittently projected uponthe object, the time relation of the periods of projection and theperiods of occultation bearing of course the same relation to each otheras those pointed out above. r

While it is thought that the theory above discussed is a trueexplanation of the phenomena described, it is by no means insisted thatit is correct or complete,

In the claims the expression loosely cohering is intended to include allobjects of which parts are freely movable with respect to one another.

I claim.

1. A method of producing color effects which consists in projectingsuccessively and intermittently separate beams of differently coloredlight upon a moving object at such a rate of succession that differentparts of the moving object exhibit different color effects, the ratebeing at the same time such that the light effect produced upon astationary ob ject is a uniformly blended color.

2. A method of producing color effects which consists in projectingsuccessively and intermittently separate beams of differently coloredlight upon moving object having a large number of independently movingparts, at such rate of succession that the different parts exhibitseparate and distinctive color effects.

8. A method of producing color effects which consists in setting anobject having loosely cohering parts into a state of agitation andsuccessively and intermittently pro jecting separate beams ofdifi'erently colored light upon said object, the rate of successionbeing so rapid that when the object is at rest a uniform blended coloris produced, and that when the object is agitated different distinctcolor effects are produced.

In testimony whereof, I affix my signature.

ALLERTON S. CUSHMAN.

